Toughness Tests on CPM-154

[Larrin]

I did a range of heat treating experiments with CPM-154 to try to find optimal combinations for good toughness and overall properties. And I show where the toughness of CPM-154 compares with other stainless knife steels. I also did a comparison with a previous toughness measurement which does not line up. https://knifesteelnerds.com/2020/03/16/ ... periments/

[The Mastiff]

Good article Larrin. You are doing a lot of work to write these. Thanks!

Also, I'm guessing if one were to get around to checking it's the 19C that really isn't lining up. I'd think the values listed couldn't be replicated by your tests. I'm not saying it's a bad steel but I don't think it's going to score that high during retests.

Joe

[JuPaul]

That's really interesting. In a recent thread someone asked which stainless steels were the toughest, and I noticed that in your charts, CPM-154 seemed to be much tougher at equal hardnesses than other common stainless steels. Interesting to see why that happened as well as the new "corrected" numbers that put it more in line with m390 and s35vn.

[Larrin]

Good article Larrin. You are doing a lot of work to write these. Thanks!

Also, I'm guessing if one were to get around to checking it's the 19C that really isn't lining up. I'd think the values listed couldn't be replicated by your tests. I'm not saying it's a bad steel but I don't think it's going to score that high during retests.

Joe

The 19C27 has much less carbide than many of the other stainless steels, so I wouldn't be so sure.

[TomAiello]

Random question: Is it true that RWL-34 is named for Robert Loveless? Does anyone know?

[Cycletroll]

Thank you Larrin! I've always wondered how CPM-154 could have such higher toughness numbers. In use it has seemed reasonably tough but but not remarkably more so than s35vn, Cruwear, or m390/204p.
I have a Demko custom AD10 in CPM-154 and have often wondered what his heat treat is like.
Really appreciate all your hard work and concisely written articles.

[Larrin]

Random question: Is it true that RWL-34 is named for Robert Loveless? Does anyone know?

Yes. https://damasteel.se/story-of-rwl34/

[elena86]

It's a mistery to me why Spyderco doesn't use 154CM ... more...

[Deadboxhero]

It's a mistery to me why Spyderco doesn't use 154CM ... more...

[curlyhairedboy]

Thanks for the article, Larrin! I always remember that charpies are a strange beast. Sometimes they just won't do what you expect...

[Larrin]

Thanks for the article, Larrin! I always remember that charpies are a strange beast. Sometimes they just won't do what you expect...

I think in general we have had consistent results with it but this one case has been different.

[curlyhairedboy]

Thanks for the article, Larrin! I always remember that charpies are a strange beast. Sometimes they just won't do what you expect...

I think in general we have had consistent results with it but this one case has been different.

given the revised results for CPM-154, do you think the estimation for Damasteel toughness also needs to be revised downward?

[Larrin]

given the revised results for CPM-154, do you think the estimation for Damasteel toughness also needs to be revised downward?

Did I give an estimate for Damasteel toughness?

[curlyhairedboy]

given the revised results for CPM-154, do you think the estimation for Damasteel toughness also needs to be revised downward?

Did I give an estimate for Damasteel toughness?

not really, but it was discussed in your Damacore article.

[Larrin]

given the revised results for CPM-154, do you think the estimation for Damasteel toughness also needs to be revised downward?

Did I give an estimate for Damasteel toughness?

not really, but it was discussed in your Damacore article.

Oh ok, I was mostly providing guesses there, noting that it could be 50:50 contribution of both steels or a worst-case where the more brittle steel limits the toughness of the overall steel.

[Larrin]

Thanks for the positive comments everyone.